如何触发updateUIView of UIViewRepresentable？

Question

我正在尝试将uiView从SpritzSwift实现到SwiftUI应用程序，但是在第一次呈现之后，我无法让它更新。驱动UIView的管理器正在工作，但UIView本身没有更新。我希望视图控制器中的UiView.setNeedsDisplay()或者包装器中@Bindable变量中的更改会触发updateUIView，但不会触发骰子。

无论我对UiView或它的包装做了什么更改，它都不会被更新(例如，在代码示例中，背景永远不会被更新以清除颜色)。如何更新此视图？

以下是SwiftUI代码：

import SwiftUI
struct Content: View {

    @State public var ssManager:SpritzSwiftManager = SpritzSwiftManager(withText: "", andWordPerMinute: Int(200))
    @State public var ssView:SpritzSwiftView = SpritzSwiftView(frame: CGRect(x: 0, y: 0, width: 200, height: 600 ))
    @State private var currentWord = ""
    
    var body: some View {
        VStack {
            Text("SpritzTest")
                .padding()
            let spritzUIView = SpritzUIViewRepresentable(SpritzView: $ssView,SpritzViewManager:$ssManager, CurrentWord: $currentWord)
            spritzUIView.padding()
            Button(action:
                    {
                        ssManager  = SpritzSwiftManager(withText: "Text try one two three", andWordPerMinute: 200)
                        spritzUIView.SpritzView = SpritzSwiftView(frame: CGRect(x: 0, y: 0, width: 200, height: 40 ))
                        spritzUIView.SpritzView.backgroundColor = .clear
                        ssManager.startReading { (word, finished) in
                            if !finished {
                                self.ssView.updateWord(word!)
                                currentWord = word!.word
                                spritzUIView.CurrentWord = currentWord

                            }
                        }
                    })
            {
                Text("Start")
            }
        }
    }
}

包装是这样的：

struct SpritzUIViewRepresentable : UIViewRepresentable{
    @Binding var SpritzView:SpritzSwiftView
    @Binding var SpritzViewManager:SpritzSwiftManager
    @Binding var CurrentWord:String
    
    func makeUIView(context: Context) -> SpritzSwiftView {
           return SpritzView
       }
       func updateUIView(_ uiView: SpritzSwiftView, context: Context) {
       }
}

Answer 1

您需要在UIKit中创建makeUIView视图，并通过绑定传递仅依赖的数据。当相关的状态-真相来源发生变化时，绑定更改调用updateUIView，在那里您应该更新您的UIKit视图。

这里仅提供简化的演示草图，以显示概念(可能有排印)：

struct SpritzUIViewRepresentable : UIViewRepresentable{
    @Binding var currentWord: SpritzSwiftWord
    @Binding var backgroundColor: UIColor
    
    func makeUIView(context: Context) -> SpritzSwiftView {
        // create and configure view here
        return SpritzSwiftView(frame: CGRect.zero) // frame does not matter here
    }

    func updateUIView(_ uiView: SpritzSwiftView, context: Context) {
       // update view properties here from bound external data
       uiView.backgroundColor = backgroundColor
       uiView.updateWord(currentWord)
    }
}

按钮现在只需更改模型数据。

    VStack {
        Text("SpritzTest")
            .padding()
        SpritzUIViewRepresentable(backgroundColor: $backgroundColor, SpritzViewManager:$ssManager, currentWord: $currentWord)
           .padding()
        Button(action:
            {
                ssManager  = SpritzSwiftManager(withText: "Text try one two three", andWordPerMinute: 200)

                self.backgroundColor = .clear
                ssManager.startReading { (word, finished) in
                    if !finished {
                        self.currentWord = word
                    }
                }
            })
        {
           Text("Start")
        }

假设更新的属性

@State private var currentWord = SpritzSwiftWord(word: "")
@State private var backgroundColor = UIColor.white         // whatever you want